Now that we have created a basic "stub" interface that Xcode will build successfully, we need to go back and fill in the final details to complete our interface definition:
Often when we are developing program code it needs to contain literal values – for example, a number or strings. Rather than using literal values in the body of our code, we will define symbols in our
.h file and then use those symbols in the body of our program code.
NewDefaults.hfile and add the following code to define the literal values that we are going to be using in the body of our code. Now is a good time to read the comments in the program code ...